How to force a default on Location Name and disable/protect form input

tagging.

Note that this code is created for the 3.1 version, not the 3.0 version.

You can't use hook_form_alter() for this because at that stage the field is only a collections of the location settings used to create the fields that will be displayed.

The location module provides a hook for this, called hook_locationapi(&$obj, $op, $a3 = NULL, $a4 = NULL, $a5 = NULL)
The field_expand $op is where locations fields are created and you can use that to modify the different fields of a location.

Here is an example that sets the default value for and then disables the 'name' field of the locations.
If you want you could add to this code some checks to determine which node type the user is currently adding/editing.

<?php
/**
 * Implementation of hook_locationapi().
 */
function mymodule_locationapi(&$obj, $op, $a3 = NULL, $a4 = NULL, $a5 = NULL) {
  switch ($op) {
    case 'field_expand':
      // For the field_expand $op, $a3 is the field name.
      switch ($a3) {
        case 'name':
          // This will be array_merged in with the field definition.
          return array(
            '#disabled' => 'TRUE',
            '#default_value' => 'This is the default text for the name field',
          );
      }
      break;
  }
}
?>